ARMSTRONG, JOHN, senior (1784–1829), physician, was born, 8 May 1784, at Ayres Quay, near Bishop Wearmouth, county Durham, where his father, George Armstrong, a man of humble birth, was a superintendent of glass works. He was educated at first privately and afterwards studied medicine at the university of Edinburgh, where he graduated M.D. in 1807 with a dissertation, 'De Causis Morborum Hydropicorum.' He practised at his native place and in the adjoining town of Sunderland, and was physician to the Sunderland Infirmary. In 1811 he married Sarah, daughter of Mr. Charles Spearman, by whom he left a family, including a son John, who became bishop of Grahamstown [q. v.]. While at Sunderland he published, besides several memoirs in the 'Edinburgh Medical Journal,' two works, 'Facts and Observations relative to the Fever commonly called Puerperal' (London, 1814), and 'Practical Illustrations of Typhus and other Febrile Diseases' (London, 1816), by which he became favourably known to the medical profession. In 1818 he removed to London and published 'Practical Illustrations of the Scarlet Fever, Measles, Pulmonary Consumption' (London, 1818), which added to his reputation. In the next year he was appointed physician to the London Fever Institution (now called Hospital), an office which he resigned in 1824, and in 1820 became licentiate of the College of Physicians.

Dr. Armstrong rapidly acquired a large practice and also became a very successful and popular teacher of medicine. In 1821 he joined Mr. Grainger, an eminent teacher of anatomy, as lecturer on medicine at the school at that time being founded by the latter in Webb Street, which, before the complete development of the great hospital schools, was one of the most important in London. In 1826 he joined Mr. Bennett in founding another school in Little Dean Street, Soho, and for some time lectured on medicine in both institutions. In 1828 failing health compelled him to give up teaching, and he died of consumption on 12 Dec. 1829, at the early age of 45.

There can be no doubt of Dr. Armstrong's great energy and brilliant talents, though the rapidity of his success and the fact of his being unconnected with any of the greater medical schools caused his career to be watched with much surprise and possibly a little jealousy. His opinion was, however, highly valued by his professional brethren.

Dr. Armstrong's works on fevers became extremely popular in this country and America, and they have the merit of being founded entirely on his own observations. Their importance has, however, been greatly diminished by later discoveries, and especially by the discrimination of several kinds of fever which were at that time confounded together. The latter consideration probably explains the changes that Armstrong's own views underwent in relation to typhus, which he in his earlier works asserted to be contagious, but in his later memoirs (Lancet, 1825) attributed to a malarial origin. In treatment Armstrong was an ardent advocate of the antiphlogistic system, and made a copious use of bleeding.

His controversy with the College of Surgeons arose out of an attempt on the part of that body to discourage private medical teaching by refusing to accept certificates except from the recognised hospitals and their medical schools. With the College of Physicians he was equally displeased on account of his having been rejected when he first presented himself as a candidate for the licentiateship, an accident which may often happen when a physician established in practice has to undergo examination on subjects with which he was familiar as a student. Dr. Armstrong is described by his friend Dr. Boott as a man of high integrity, absorbed in his profession, of gentle and reserved character, with much power of sympathy. He appears to have had few intellectual interests outside of his daily work, and spoke with some contempt of 'learned physicians.'

Besides the above, Dr. Armstrong was author of: 1. 'An Address to the Members of the Royal College of Surgeons on the injurious conduct and defective state of that Corporation with reference to Professional Rights, Medical Science, and the Public Health,' London, 1825. 2. 'The Morbid Anatomy of the Stomach, Bowels, and Liver, illustrated by a series of plates with explanatory letterpress, and a summary of the symptoms of the acute and chronic affections of the above-named organs,' 4to, London, 1828 (unfinished). 3. 'Lectures on the Morbid Anatomy, Nature, and Treatment of Acute and Chronic Diseases,' edited by Joseph Rix (after the author's death), London, 1834.

[Boott's Memoir of the Life and Medical Opinions of John Armstrong, in 2 vols., 1833; Munk's Roll of College of Physicians (1878). iii. 216.]